I posted this on another thread, but thought it would be appropriate here too...
I had to call the IRS about a separate issue yesterday, and when I finally got a live person (only took 30ish minutes!

), I mentioned the delay in processing that I saw on the website. I was informed that even though a lot of returns were accepted on 2/14, most of those returns did not start processing in the IRS system until Monday, 2/18. This is what is causing the lack of status change on Where's My Refund. I was told that hopefully, most of the returns that were accepted on 2/14 will have some sort of update by Monday 2/25 (since even though the website updates overnight, the biggest updates are done overnight on Wednesdays and Sundays)...
Hope this helps ease some worries! Of course, this is the IRS we're talking about...